But because all the OSes are going to be extended to the mobile, all the vendors are making changes to the DE at the expense of some discomfort of the users.
Desktops are not smartphones,. The main differences are far more screen real estate (true even on a netbook with the screen the size of a tablet
Certainly, a single unified UI is convenient for developers. But if the price of developer convenience is mass migration to the competition, it's not worth paying.
Thus spake the master programmer: "After three days without programming, life becomes meaningless." -- Geoffrey James, "The Tao of Programming"